1. Field of the Invention
The invention relates to latching devices. More particularly, the invention relates to latching devices which are particularly useful for animal cages.
2. State of the Art
A portion of a state of the art animal cage is shown in prior art FIG. 1. The cage 10 is provided with a hinged door 12 and a spring biased latch 14 which is located to engage or abut a tab 16 on the door 12 when the door is closed. Details of the latch 14 are shown in prior art FIGS. 2-5.
As seen best in prior art FIGS. 2 and 3, the latch 14 generally includes a U-shaped bracket 18 having a front flange 20 and a rear flange 22, each of which defines a keyed hole 24, 26, an L-shaped bolt 28 having two spaced apart flanges 30, 32 (typically formed by crimping), and a coil spring 34. The bolt 28 is placed so that it extends through the holes 24, 26 as shown in FIGS. 2, 4, and 5. The spring 34 is arranged coaxially with the bolt 28 and is located between the rear flange 22 of the bracket 18 and the first flange 30 on the bolt 28 thereby biasing the bolt 28 forward into the hole 24. As seen best in FIGS. 2 and 3, when the flange 32 on the bolt 28 is aligned with the keyed hole 24 in the front flange 20 of the bracket 18, the biasing action of the spring 34 moves the bolt 28 forward through the hole 24 into a "latched" position. In the position shown in FIG. 2, the end of the bolt 28 can engage of abut the tab 16 (FIG. 1) on the door to latch the door shut. From the foregoing it will be appreciated that the latch 14 can be moved to an "unlatched" position by pulling the bolt 28 back against the spring 34 as shown in FIG. 4. The bolt can be held in the "unlatched" position by rotating it so that the flange 32 is no longer in alignment with the keyed hole 24 as shown in FIG. 5.
The prior art latch 14 provides a simple and inexpensive means for locking the door of an animal cage so that the animal cannot escape. However, as shown in FIGS. 6-8, the latch 14 is so simple in its design that it is possible to disable the latch by pulling the bolt 28 back far enough so that the end of the bolt is pulled out of the hole 24 as shown in FIG. 7. When released from the position shown in FIG. 7, the bolt 28 is likely to fall away from the bracket 18 as shown in FIG. 8, at which time the latch is no longer effective. Those skilled in the art of animal care will appreciate that some animals possess the physiological ability as well as the intelligence to disable the latch in this manner. In particular, some large birds have demonstrated the ability to learn how to disable the state of the art latch and thereby release themselves from the cage.